Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark this read-only/non-destructive, and the description adds genuinely new behavior: what happens on a WHOIS failure (the TLD is not counted as taken but reported as a missing measurement), and the important consequence that 'no alternatives found' differs from 'not all TLDs checked'. That is exactly the kind of failure-mode disclosure annotations cannot carry.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the action and trigger, then the mechanism, then the failure semantics. Dense but each clause carries information; the long em-dash sentence is slightly heavy but not padded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter read-only lookup with no output schema, the description covers trigger, mechanism, result shape (up to 5 hits) and error semantics, leaving nothing an agent needs missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

One required parameter with 100% schema description coverage, so the schema already documents the 'domain' argument fully. The description adds the TLD set being probed, which is tool behavior rather than parameter meaning, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (vorschlagen), resource (Domain-Alternativen) and scope: WHOIS checks of the same name across a named curated TLD list, returning up to 5 available hits. An agent can distinguish this from check_domain_availability or prepare_domain_order without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The trigger condition is explicit – use it when the desired domain is already taken ('wenn die gewünschte Domain vergeben ist'). It does not name the sibling it complements/contrasts with (check_domain_availability), so routing is clear but not fully explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.